If it’s just (-4) with nothing in front the answer is -4
        
             
        
        
        
Answer: 31.43 cm
Step-by-step explanation:
The length of an arc  is calculated using the formula:
 X 2
 X 2 r
r
where : theta is the angle in degree
r = radius
If the angle is given in Radian , the length can be calculated using the formula:
L = r∅
Since , the angle is given in degree , we will use the first formula.
L =  X 2
 X 2 r
r
L =  X 2 X π X 15
 X 2 X π X 15
L =  X 2 X
 X 2 X  X 15
 X 15
L = 
L = 31.42857143
L ≈ 31.43 cm
 
        
             
        
        
        
It is false or 8/9 is equal to 1
        
                    
             
        
        
        
Complete Question 
A biologist reports a confidence interval of (3.5,4.9) when estimating the mean height (in centimeters) of a sample of seedlings. What is the estimated margin of error and the sample mean?
Answer:
The  margin of error is  
 The  sample mean is  
Step-by-step explanation:
from the question we are told that 
    The  upper limit is  
     The  lower limit is  
Generally the margin of error is mathematically represented as 
       
       
      
Generally the sample mean is mathematically evaluated as 
         
 =>    
=>    
 
        
             
        
        
        
Step-by-step explanation:
given f(x) = 2/x and g(x) = 2/x
f(g(x)) = 2/(g(x)) = 2/2/x = x/2 × 2 = x
g(f(x)) = 2/(f(x)) = 2/2/x = x/2 × 2 = x
therefore they are inverses 
since f(g(x)) = g(f(x)) = x.